Presentation on theme: "Efficacy of computed tomography scout film and kidney ureter bladder radiograph in detecting urinary calculi. Introduction Urolithiasis is one of the most."— Presentation transcript:
Efficacy of computed tomography scout film and kidney ureter bladder radiograph in detecting urinary calculi. Introduction Urolithiasis is one of the most common urological conditions(Johnson, Wilson et al.). Currently, patients who present with features suggestive of urolithiasis are commonly investigated with non-contrast helical computed tomography (NCHCT) and XRay KUB simultaneously. NCHCT has been shown to be a superior investigation for urolithiasis, by being more sensitive than XRay KUB and intravenous urogram (IVU) (Johnston et al.). Conclusions Both XRay KUB and CT Scout film have a low sensitivity and specificity for detecting urolithiasis. They are not efficacious initial investigations. Almost all stones (98%) visible on scout film are also visible on XRay KUB. We therefore suggest that patients can initially undergo NCHCT and review of scout film. Stones that are visible on initial scout film can be followed up with XRay KUB. If stones are not visible initially on scout film, then a subsequent XRay KUB can be performed to determine whether the stone is visible- although the increase in detection would be low. These suggestions would minimise initial radiation exposure and cost. Results 113 urinary calculi were detected in 50 patients, with average an average width of 5.1mm. XRay KUB detected 54 (47.8%) stones while CT Scout film detected 43 (38%) (P<0.001) (table 1). In all instances except 1, all stones visible on CT scout film were visible on XRay. Using NCHCT scan as the gold standard investigation, XRay KUB had a sensitivity of 67% and specificity of 25% (table 1). Scout film had a sensitivity of 59% and specificity of 50% (table 3). Methods We identified 50 patients between January 2010 and August 2012 who presented with clinical features suggestive of urolithiasis, and who had a CT and XRay on the same day. An independent radiologist reviewed all XRays and CT scout films, and recorded the number of stones seen and their position. These were then compared to the original CT scan, and report. The Chi-Square test was used to determine the statistical significance for the proportion of stones found with XRay versus scout film. Sensitivity and specificity were determined by cross- tabulating the incidence of stone detection in both XRay KUB and CT Scout film by comparing against NCHCT as the gold standard investigation. Aim In this study we aim to investigate the comparative efficacy of CT Scout film and XRay KUB, as defined by sensitivity and specificity. Therefore we may be more able to identify their roles in initial investigation and follow up. References Johnson CM, Wilson DM, O'Fallon WM, Malek RS, Kurland LT. Renal stone epidemiology: a 25-year study in Rochester, Minnesota. Kidney International.16(5):624-631. Johnston R, Lin A, Du J, Mark S. Comparison of kidney-ureter-bladder abdominal radiography and computed tomography scout films for identifying renal calculi. BJU International.104(5):670-673. Xray KUB detected almost every stone visible on scout film. Given that the scout film is generated during the initial NCHCT scan, the need for an initial XRay KUB can be determined after reviewing the initial scout film (figure 1). Sam S Farah, Neville Tan, Dri Appu, A/Prof Mark Frydenberg, A/Prof Sree Appu Department of Urology Monash Medical Centre Moorabbin Victoria. Monash Health. No. 131 Posters Proudly Supported by:
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